Jose Claudio Faria
2006-Feb-14 00:35 UTC
[R] ANOVA: Help with SSQ decomposition and contrasts
# Dear R list, # # A have a doubt about SSQ decomposition and contrasts with ANOVAs. # So, I would like a tip from more advanced R users. # Below my data, the basic script and my doubts: # Data r = paste('r', gl(3, 8), sep='') e = paste('e', rep(gl(2, 4), 3), sep='') tra = sort(paste('t', rep(1:6, 4), sep='')) y = c(26.2, 26.0, 25.0, 25.4, 24.8, 24.6, 26.7, 25.2, 25.7, 26.3, 25.1, 26.4, 19.6, 21.1, 19.0, 18.6, 22.8, 19.4, 18.8, 19.2, 19.8, 21.4, 22.8, 21.3) dF = data.frame(r, e, tra, y) # Graphic par(mfrow=c(2,1)) interaction.plot(dF$r, dF$e, dF$y, col = 'blue', ylab = 'Y', xlab = 'R') interaction.plot(dF$e, dF$r, dF$y, col = 'blue', ylab = 'Y', xlab = 'R') # ANOVAs av0 = aov(y ~ tra, data=dF) summary(av0) av1 = aov(y ~ r*e, data=dF) summary(av1) av2 = aov(y ~ r/e, data=dF) e_r = summary(av2, split = list('r:e' = list( 'e1 vs e2/r1' = 1, 'e1 vs e2/r2' = 2, 'e1 vs e2/r3' = 3))) e_r av3 = aov(y ~ e/r, data=dF) r_e = summary(av3, split = list('e:r' = list( 'r/e1' = c(1,3), 'r/e2' = c(2,4)))) r_e # My Doubts # a) How to make SSQ decomposition to complete the ANOVA below? # Df Sum Sq Mean Sq F value Pr(>F) # e 1 19.082 19.082 14.875 0.001155 # e:r 4 156.622 39.155 30.524 8.438e-08 # e:r: r/e1 2 87.122 43.561 33.958 7.776e-07 # r1 vs (r2, r3) 1 ? ? ? ? # r2 vs r3 1 ? ? ? ? # e:r: r/e2 2 69.500 34.750 27.090 3.730e-06 # r1 vs (r2, r3) 1 ? ? ? ? # r2 vs r3 1 ? ? ? ? # Residuals 18 23.090 1.283 # b) How to make SSQ decomposition to complete the ANOVA below? # Df Sum Sq Mean Sq F value Pr(>F) # e 1 19.082 19.082 14.875 0.001155 # e:r 4 156.622 39.155 30.524 8.438e-08 # e:r: r/e1 2 87.122 43.561 33.958 7.776e-07 # r2 vs (r1, r3) 1 ? ? ? ? # r1 vs r3 1 ? ? ? ? # e:r: r/e2 2 69.500 34.750 27.090 3.730e-06 # r2 vs (r1, r3) 1 ? ? ? ? # r1 vs r3 1 ? ? ? ? # Residuals 18 23.090 1.283 # TIA, -- Jose Claudio Faria Brasil/Bahia/UESC/DCET Estatistica Experimental/Prof. Adjunto mails: joseclaudio.faria at terra.com.br joseclaudio.faria at oi.com.br jc_faria at uesc.br jc_faria at uol.com.br tel: 73-3634.2779